Commonly assigned U.S. Pat. No. 5,546,557 is incorporated for its showing of a system for storing and managing plural logical volumes in each of several physical media volumes in an automated data storage library.
Commonly assigned U.S. Pat. No. 5,870,732 is incorporated for its showing of an automated virtual data storage and retrieval library.
Commonly assigned U.S. Pat. No. 5,805,864 is incorporated for its showing of a virtual tape storage system useful with the present invention.
1. Field of the Invention
The present invention relates to digital data storage systems and more particularly the invention concerns a system for the identification of particular cartridges used for storing data in a virtual tape system in order to protect the data on the particular cartridge by preventing the overwriting of data and to recover from mistakenly identifying an import volume as a scratch volume.
2. Description of the Related Art
A critical aspect of digital data storage operations is the identification of a particular cartridge and its placement in a logical library to signify whether the cartridge can have its data overwritten or whether the data may exist only in that volume and must not be overwritten. There is a need to protect the data on a specific cartridge from being inadvertently overwritten if the data is unique and may not exist in any other manner. The protection of the data and the cartridge needs to be convenient for an operator that is inserting the cartridge into a library storage system.
Data storage libraries use portable media items such as magnetic tape or optical cartridges stored in a convenient form for easy handling in a storage system. In such libraries, one part of a read/write operation typically involves the retrieval of the appropriate cartridge. In a read operation, retrieval of a desired cartridge involves removing the cartridge from one of the many storage bins in the library and transferring the cartridge-to a drive. Like read operations, write operations may also be directed to a specific cartridge. However, some write operations are performed simply to store data in any available cartridge. These operations are called xe2x80x9cscratch mountsxe2x80x9d, since the write procedure may be completed by mounting and then writing to any blank or xe2x80x9cscratchxe2x80x9d cartridge of the library. Scratch mounts may be contrasted, for example with write operations that serve to update or supplement data previously written to a cartridge.
Today, a library data server contains one or more servers handling the optical or magnetic media onto which the data is stored. Magnetic tape storage is presently preferable to optical storage and therefore this invention will be described using a magnetic tape cartridge library system. It should be understood that this invention is equally adaptable to both.
A library data server generally includes one or more tape servers into which a plurality of tape cartridges are stored to access the data stored on the individual tape cartridge. The library data server automates the retrieval, storage and control of tape cartridges and the data on the cartridges. The library data server includes an operator panel, a tape subsystem with drives, a library manager, cartridge storage cells, a cartridge accessor and an input/output station. A virtual tape server can be included and includes additional cartridge storage and a controller.
The logical library to which a cartridge is associated, is determined using volser range tables. The volser range tables define which range volsers are to be associated with a logical library. When a cartridge is inserted into the library, the volser ranges identify which logical library to which the cartridge is to be assigned. The cartridge can be assigned to a standard logical type library or one of the virtual tape server VTS logical libraries. When the cartridge is assigned to a logical library it is put into an insert category. The host that owns the new volume changes the volumes category to a xe2x80x9cscratchxe2x80x9d volume. Subsequently, any data on the volume can be overwritten. With the addition of export/import capabilities, cartridges can be used as exported stack volumes containing exported logical volumes. With this addition to the virtual tape servers (VTS) a cartridge could be assigned to a non-VTS logical library, a VTS logical library, or be identified as an exported stacked volume for use in an import operation. The data on the exported stack volume may only exist on that volume and must not be overwritten.
A number of different approaches may be used to satisfy xe2x80x9cscratch mountsxe2x80x9d. One simple approach is for a human operator or robot to select the cartridge, manually transfer the cartridge to the drive, and then direct the drive to mount the cartridge. The problem is that the volume may be improperly selected and may be assigned to a location where the information may be overwritten. With the addition of the particular new export/import conveniences to a VTS, a need is created to protect the data of the exported stacked volume from being inadvertently overwritten. This protection needs to be convenient for an operator that is inserting the cartridges into the library.
Broadly, the present invention concerns an article of manufacture and a system and method for controlling a cartridge storage system by providing a protection under the convenience of an operator that is inserting the cartridges into a library. The invention may be implemented by providing a convenience input/output station that can be set to one of two modes based on the capabilities of the virtual tape servers in the library. If none of the virtual tape servers in the library are export/import capable, then the convenience input/output station is set to the insert mode. This operates the station in the same manner as in the prior art. However, if one or more of the virtual tape servers in the library are export/import capable, the convenience input/output station is set to the import mode. The import mode causes possible import cartridges to be set to an unassigned category when they are inserted. Volumes in this category cannot be accessed by any host or virtual tape server. Means are provided for the operator to identify which of the unassigned volumes are export stacked volumes, which volumes should be evaluated as insert volumes, and which volumes need to be ejected. Further means are provided for the operator to eject a volume identified as an insert volume. This provides the operator with a means to recover an exported stacked volume that was mistakenly identified as an insert volume.
The convenience input/output station can be in one of two modes, import or non-import depending on the capabilities of the virtual tape servers in the library and the configuration of the library.
The invention provides a number of distinct advantages. The present invention provides a method and article of manufacture to prevent exported logical volume data from being overwritten especially when the volume contains information that is unique and available in no other format. The invention further provides means by which an operator can recover from mistakes where an import volume is identified as a scratch volume which is capable of accepting new data.
An object of the present invention, therefore, is to provide a tape library data server that includes an article of manufacture and a method of preventing exported logical volume data from being overwritten.
Another object of the present invention is to provide a means and a process to recover from errors where an import volume is identified as a scratch volume.
Still another object of the invention is to provide a process of moving volumes in the import category to the appropriate insert category based on the volser ranges and permitting the ejection of the volume if necessary.
Yet another object of the invention is to provide a tape library data server which includes virtual tape servers that are capable of handling export/import volumes.
The foregoing, and other objects, features and advantages of the invention will become more apparent to those skilled in the art after considering the following detailed description in connection with the accompanying drawings in which reference numerals designate like parts throughout.